#include<stdio.h>
 void change(int *a,int *b)
 {
    int temp=0;
    temp=*a;
    *a=*b;
    *b=temp;
 }
 int main(void){
    int a=10;
    int b=20;
    printf("a=%d,b=%d\n",a,b);
    change(&a,&b);
    printf("a=%d,b=%d\n",a,b);
    return 0;
 }